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Allergy Medicines

What Allergy Medicines Are For

When a person has allergies, he or she may be sensitive to a variety of common substances such as pollen, mold, animal dander, or dust. Seasonal allergies, often referred to as "hay fever," are caused by reactions to types of pollen found in trees, grass, flowers, or weeds. When exposed to any of these pollens, an allergy sufferer may experience sneezing and runny nose (allergic rhinitis), itchy or watery eyes (allergic conjunctivitis), itching of the skin, or hives. Allergy medicines, most of which are known as antihistamines, relieve allergy symptoms. Some antihistamines also treat some symptoms of the common cold such as runny nose and sneezing.

How Allergy Medicines Work

Allergy products, like all over-the-counter (OTC) medicines, contain certain active ingredients that make the products work in the human body. The product’s active ingredients, including how much of a substance is in each dose, are listed first on the Drug Facts label.

There are two basic types of allergy medicines, antihistamines and nasal allergy symptom controllers:

Antihistamines

During an allergic reaction, the body releases a chemical called histamine. Histamine attaches to certain body cells, such as the cells inside the nose, causing them to swell and create the allergic symptoms. Antihistamines work by preventing this histamine cell attachment, thereby blocking the allergic effects of histamine. Allergy medicines may also contain other active ingredients to treat related symptoms such as nasal congestion or headache.

Oral allergy medicines containing antihistamines are available to consumers over the counter in liquid and pill form. There also are over-the-counter eye drops that contain antihistamines.

Antihistamine active ingredients in allergy medicines include:

Nasal Allergy Symptom Controllers (Mast Cell Stabilizers)

Like antihistamines, nasal allergy symptom controllers (also known as mast cell stabilizers) also reduce the effects of histamine, but in a different way. Nasal allergy symptom controllers reduce how much histamine is released into the body when a person has an allergic reaction.

Nasal allergy symptom controllers containing cromolyn sodium are applied directly inside of the nose. They are available to consumers over the counter in the form of nasal sprays.

The nasal allergy symptom controller ingredient contained in allergy medicines is:

*Not all products marketed under a brand contain the same ingredients. Please read the OTC Drug Facts label carefully for active ingredient information.

Tips for the Safe Use of OTC Allergy Medicines

  • Always read the OTC Drug Facts label carefully. The label tells you everything you need to know about the medicine including the ingredients, what you are supposed to use it for, how much you should take, and when you should not take the product.
  • Allergy symptoms can be severe. If you have rapid or difficult breathing, or if you are wheezing, seek medical attention immediately or call 9-1-1.
  • Some oral allergy medicines may cause excitability or nervousness.
  • Some oral allergy medicines contain more than one active ingredient to treat additional symptoms such as nasal congestion or headache. You should only treat the symptoms you have.
  • Some oral allergy medicines may cause drowsiness.
  • If you have emphysema, chronic bronchitis, glaucoma, or an enlarged prostate gland, talk to your doctor before taking an oral allergy medicine.
  • Oral allergy medicines may react with certain prescription medicines. Speak with your doctor or other healthcare professional before using an allergy medicine if you are taking tranquilizers or sedatives.
  • Talk to your doctor before taking an oral allergy medicine if you have liver or kidney disease.
  • Talk to your doctor before using a topical allergy medicine if you have a fever, discolored nasal discharge, sinus pain, or wheezing.
  • If you have heart disease, high blood pressure, narrow angle glaucoma, or an enlarged prostate gland, talk to a doctor before using an OTC allergy eye drop.
  • Stop using an OTC allergy eye drop and contact a doctor if you experience eye pain, changes in vision, prolonged eye redness or irritation, or if your condition gets worse or lasts for more than three days.
  • Nasal allergy symptom controllers containing cromolyn sodium may take several days of use to take effect.
  • Brief stinging or sneezing may occur right after using a nasal allergy symptom controller.
  • Do not use a nasal allergy symptom controller to treat a sinus infection, asthma, or cold symptoms.
  • To prevent germs from spreading, do not share a nasal spray medicine with anyone else.
  • If your symptoms get worse, do not improve within two weeks, or if you develop new symptoms, stop using a nasal allergy symptom controller and contact your doctor.
  • As with most medicines, ask a healthcare professional before use if you are pregnant or breastfeeding.

Tips for Parents

All of the tips for the safe use of OTC allergy medicines in this section also apply to children. But there are some additional considerations when it comes to treating kids with allergy medicines.

  • Some OTC oral allergy medicines are available in different dosage strengths. Read the Drug Facts label carefully for appropriate child dosing information and contact a healthcare professional as directed.
  • Some oral allergy medicines may cause excitability or nervousness, especially in children. If you have any questions, contact your child’s doctor.
  • Never use any allergy medicine to sedate or make a child sleepy.
  • You can learn more about treating children's allergies with our Children's Colds vs. Allergies Checklist.

Select the ingredient below for specific information about individual ingredients and how they are labeled for children.

Keep all medicines out of the reach and sight of children.

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